doc: remove reference to old version of FreeBSD
doc: remove reference to old version of FreeBSD

FreeBSD 10 is now EOL and all testing with DPDK takes place on BSD versions
11 and 12, so we can just remove the note. The BSD ports are supported on
all non-EOL versions of BSD.

Signed-off-by: Bruce Richardson <66b9e8e8fbd5e9f41f91b0af050876182ce9d0e4@intel.com>
Acked-by: Anatoly Burakov <814e00d8f6e4e81b7ccc7e3e5a0bfec0078f0203@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk